Mechanisms regulating ribosome assembly and function in stem cells and vertebrate development.

蛋白质合成是细胞决定生长、增殖和/或分化的基础。2，6，11 - 14，14，15，18 了解蛋白质合成如何使细胞执行这些基本活动是一个重大挑战， 生物学因此，迫切需要阐明决定蛋白质合成速率的机制， 这些机制是否以细胞类型特异性的方式运作，以在细胞中赋予新的调节层， 控制基因表达。为了探索这些问题，两个正交但互补的研究项目， 即方案1和方案2。方案1研究了涉及的新因素和机制 在干细胞中核糖体的调节装配中。方案1是建立在我实验室最近的研究基础上的， 其他研究表明，干细胞依赖于核糖体组装，以确保足够的蛋白质合成率 以及从自我更新到分化的转变。2，3，6，11 - 14，14，15，18我的实验室已经表征了 人细胞中的小亚基（SSU）加工体，并将DNA依赖性蛋白激酶（DNA-PK）鉴定为 造血干细胞中核糖体组装和蛋白质合成的RNA依赖性调节因子。6因此， 计划1的近期目标是建立DNA-PK调节核糖体的机制 干细胞的生物发生程序2探讨如何定制核糖体组装和功能有助于 蛋白质合成和选择性mRNA翻译。方案2强调， 研究结果表明，核糖体的组成和活性在细胞类型和组织中受到动态调节， 特异性方式，允许蛋白质表达以精确的时间和空间精度进行调节。 计划2的直接目标是生成体内模型系统，以了解细胞如何创建和 调节核糖体异质性以及这种形式的调节对适当细胞功能的重要性， 有机体发育为了解决这些问题，我们已经产生了转基因斑马鱼， 组成不同和发育调节的核糖体已经被遗传标记，这是一种独特的， 在体内发育模型系统中研究核糖体功能方面的有力工具。来 在接下来的五年里，我们希望计划1和计划2能够揭示调节核糖体组装的新机制， 在干细胞和脊椎动物发育中的作用，并为核糖体病、组织- 与核糖体生物发生和功能缺陷有关的特定疾病。

Protein synthesis underpins a cell’s decision to growth, proliferate and/or differentiate.2,6,11–14,14,15,18 Understanding how protein synthesis allow cells to perform these fundamental activities is a major challenge in biology. Therefore, there is a critical need to elucidate the mechanisms determining protein synthesis rates and whether these mechanisms operate in a cell type-specific manner to impart a new layer of regulation in the control of gene expression. To explore these questions, two orthogonal, but complementary, research programs, namely Program 1 and 2, have been designed. Program 1 investigates new factors and mechanisms involved in the regulated assembly of ribosomes in stem cells. Program 1 is built upon recent studies from my lab and others demonstrating that stem cells relies on ribosome assembly to ensure adequate protein synthesis rates and the transition from self-renewal to differentiation.2,3,6,11–14,14,15,18 My lab has characterized the composition of the small subunit (SSU) processome in human cells, and identified DNA-dependent protein kinase (DNA-PK) as an RNA-dependent regulator of ribosome assembly and proteins synthesis in hematopoietic stem cells.6 Thus, the immediate goal of Program 1 is to establish the mechanisms by which DNA-PK regulates ribosome biogenesis in stem cells. Program 2 explores how customizing ribosome assembly and function contributes to protein synthesis and selective mRNA translation during embryogenesis. Program 2 is underscored by recent findings suggesting that ribosomes composition and activity are dynamically regulated in a cell type- and tissue- specific manner, allowing protein expression to be regulated with exquisite temporal and spatial precision.8,12 The immediate goal of Program 2 is to generate in vivo model systems to understand how the cell creates and regulates ribosome heterogeneity and the importance of this form of regulation for proper cellular function and organismal development. To address these, we have generated transgenic zebrafish in which two compositionally distinct and developmentally regulated ribosomes have been genetically labeled, a unique and powerful tool to study functional aspects of the ribosome in an in vivo developmental model system. Over the next five years, we expect Program 1 and 2 to uncover new mechanisms regulating ribosomes assembly and function in stem cells and vertebrate development and to provide powerful insights into ribosomopathies, tissue- specific disorders linked to defects in ribosome biogenesis and function.